Ocular Surface Alterations in Atopic Patients with Shield Ulcers

Abstract

Abstract: : Purpose: To study the tear functions and ocular surface health status in atopic patients with shield ulcers. Patients & Methods:Forty–four eyes of 22 patients (14 males, 8 females; mean age:21.3 years) with atopy as well as 30 eyes of 15 age and sex matched healthy control subjects were recruited. There were 10 eyes with vernal keratoconjunctivitis and 30 eyes with atopic keratoconjunctivitis.9 eyes had shield ulcers. None of the patients or controls had any other ocular or systemic disease.All patients had the same treatment including topical antiallergic and steroids.Subjects underwent corneal sensitivity measurements, Schirmer test –I, BUT measurements, Rose–Bengal and fluorescein vital stainings, upper tarsal conjunctival impression and brush cytology(BC). Informed consents and ethic board review for the procedures were also obtained. Impression cytology (IC) specimens were evaluated by PAS and immunohistochemical staining employing Muc5AC antibodies. BC specimens obtained from upper tarsal conjunctiva were studied for expression of inflammatory cells and with Real Time PCR to assess the Muc5AC mRNA expression. Results:The mean corneal sensitivity and BUT values were significantly lower in eyes with ulcers which also had higher staining scores, compared to eyes with no ulcers and controls ( p<0.001). All eyes with ulcers had aqueous deficiency. BC revealed significantly higher numbers of inflammatory cells in eyes with ulcers. IC showed significant goblet cell loss and squamous metaplasia in eyes with ulcers compared to eyes without ulcers and controls . PAS stained IC specimens showed increased mucin pick up in eyes with ulcers .Real Time PCR showed that eyes with ulcers had 17 fold decrease in Muc5AC expression . Immunohistochemistry staining for Muc5AC in eyes with ulcers showed a scanty staining for mucin with a decrease in goblet cells. Conclusion:The inflammatory process, aqueous deficiency and decreased Muc5AC expression were thought to be important factors in the pathogenesis of atopic shield ulcers. Decreased Muc5AC expression in presence of increased PAS staining of mucin together with decreased staining for Muc5AC in IC suggests secretion of other mucins in an attempt to protect the ocular surface in eyes with shield ulcers.

Keywords: conjunctiva • immunohistochemistry • gene/expression